BACKGROUND Solitary rectal ulcer syndrome(SRUS)is a rare rectal disease with unknown etiology.Data on the genetic background in SRUS is lacking.CASE SUMMARY Here,we report the first case of SRUS in a mother-son relati...BACKGROUND Solitary rectal ulcer syndrome(SRUS)is a rare rectal disease with unknown etiology.Data on the genetic background in SRUS is lacking.CASE SUMMARY Here,we report the first case of SRUS in a mother-son relationship.Gene sequencing was conducted on the whole family,which revealed an inherited CHEK2 p.H371Y mutation.The experiment preliminarily revealed that the CHEK2 mutation did not affect the expression of CHEK2 protein,but affected the function of CHEK2,resulting in the expression level changes of downstream genes such as CDC25A.CONCLUSION SRUS is a genetic susceptibility disease where CHEK2 p.H371Y mutation may play a crucial role in the development and prognosis of SRUS.展开更多
From a safety point of view, it is important to study the damages and reliability of molten salt reactor structural alloy materials, which are subjected to extreme environments due to neutron irradiation, molten salt ...From a safety point of view, it is important to study the damages and reliability of molten salt reactor structural alloy materials, which are subjected to extreme environments due to neutron irradiation, molten salt corrosion, fission product attacks, thermal stress, and even combinations of these. In the past few years, synchrotron radiation-based materials characterization techniques have proven to be effective in revealing the microstructural evolution and failure mechanisms of the alloys under surrogating operation conditions. Here, we review the recent progress in the investigations of molten salt corrosion,tellurium(Te) corrosion, and alloy design. The valence states and distribution of chromium(Cr) atoms, and the diffusion and local atomic structure of Te atoms near the surface of corroded alloys have been investigated using synchrotron radiation techniques, which considerably deepen the understandings on the molten salt and Te corrosion behaviors. Furthermore, the structure and size distribution of the second phases in the alloys have been obtained, which are helpful for the future development of new alloy materials.展开更多
Many large and super-large copper deposits have been discovered and explored in the Tibet Plateau,which makes it the most important copper resource reserve and development base in China.Based on the work of the resear...Many large and super-large copper deposits have been discovered and explored in the Tibet Plateau,which makes it the most important copper resource reserve and development base in China.Based on the work of the research team,the paper summarizes the geological characteristics of the main copper deposits in Tibet and puts forward a further prospecting direction.A series of large accumulated metal deposits or ore districts from subduction of Tethys oceanic crust to India-Asia collisionhave been discovered,such as Duolong Cu(Au)ore district and Jiama copper polymetallic deposit.The ore deposits in the Duolong ore district are located in the lowstand domain,the top of lowstand domain,and the highstand domain of the same magmatic-hydrothermal metallogenic system,and their relative positions are the indicators for related deposits in the Bangong Co-Nujiang metallogenic belt.The polycentric metallogenic model of the Jiama copper polymetallic deposit is an important inspiration for the exploration of the porphyry mineralization related to collision orogeny.Further mineral exploration in the Tibet Plateau should be focused on the continental volcanic rocks related to porphyry-epithermal deposits,orogenic gold deposits,hydrothermal Pb-Zn deposits related to nappe structures,skarn Cu(Au)and polymetallic deposits,and the Miocene W-Sn polymetallic deposits.展开更多
Detector and event visualization are essential parts of the software used in high-energy physics(HEP)experiments.Modern visualization techniques and multimedia production platforms such as Unity provide impressive dis...Detector and event visualization are essential parts of the software used in high-energy physics(HEP)experiments.Modern visualization techniques and multimedia production platforms such as Unity provide impressive display effects and professional extensions for visualization in HEP experiments.In this study,a method for automatic detector description transformation is presented,which can convert the complicated HEP detector geometry from GDML in offline software to 3D modeling in Unity.The method was successfully applied in the BESIII experiment and can be further developed into applications such as event displays,data monitoring,or virtual reality.It has great potential in detector design,offline software development,physics analysis,and outreach for next-generation HEP experiments as well as applications in nuclear techniques for the industry.展开更多
Regulating rheological properties of water-based drilling fluids has always been a hot topic.This paper proposed a new method for regulating rheological properties of water-based drilling fluids by ultrasonic field.Th...Regulating rheological properties of water-based drilling fluids has always been a hot topic.This paper proposed a new method for regulating rheological properties of water-based drilling fluids by ultrasonic field.The experimental results showed that the ultrasound increased the viscosity and yield point of bentonite suspension by reducing the particle size of clay,destroying the network structure between clay particles,increasing the mud yield and the cation exchange capacity of bentonite,and promoting the hydration dispersion of bentonite.The change of rheological property showed a memory effect at room temperature and high temperature.Besides,the ultrasonic energy affected the network structure between clays and polymer chains,thus regulating the rheological properties of the bentonite-polymer system.For two types of drilling fluids investigated,the rheology of the poly-sulfonate drilling fluid was regulated by damaging the grid structure between additives and clays by low-power ultrasound and reducing the clay particle size by high-power ultrasound,while the rheology of the deep-water drilling fluid was mainly regulated by disentangling the spatial grid structure between additives.Additionally,ultrasound showed no effect on the lubricity,inhibition and stability of drilling fluids,which proved the feasibility of ultrasound to regulate rheological properties of water-based drilling fluids.展开更多
An explosion-welded technology was induced to manufacture the GH3535/316H bimetallic plates to provide a more cost-effective structural material for ultrahigh temperature,molten salt thermal storage systems.The micros...An explosion-welded technology was induced to manufacture the GH3535/316H bimetallic plates to provide a more cost-effective structural material for ultrahigh temperature,molten salt thermal storage systems.The microstructure of the bonding interfaces were extensively investigated by scanning electron microscopy,energy dispersive spectrometry,and an electron probe microanalyzer.The bonding interface possessed a periodic,wavy morphology and was adorned by peninsula-or island-like transition zones.At higher magnification,a matrix recrystallization region,fine grain region,columnar grain region,equiaxed grain region,and shrinkage porosity were observed in the transition zones and surrounding area.Electron backscattered diffraction demonstrated that the strain in the recrystallization region of the GH3535 matrix and transition zone was less than the substrate.Strain concentration occurred at the interface and the solidification defects in the transition zone.The dislocation substructure in 316H near the interface was characterized by electron channeling contrast imaging.A dislocation network was formed in the grains of 316H.The microhardness decreased as the distance from the welding interface increased and the lowest hardness was inside the transition zone.展开更多
1.Introduction Sudden cardiac death(SCD)refers to sudden death due to a variety of cardiac causes.It is manifested as a sudden loss of consciousness,cardiac arrest,and respiratory arrest and generally shows early symp...1.Introduction Sudden cardiac death(SCD)refers to sudden death due to a variety of cardiac causes.It is manifested as a sudden loss of consciousness,cardiac arrest,and respiratory arrest and generally shows early symptoms that are atypical and not easily detected[1].According to a recent study,nearly 544000 patients suffer from SCD every year in China[2].展开更多
Considering the fact that memristors have the characteristics similar to biological synapses, a fractional-order multistable memristor is proposed in this paper. It is verified that the fractional-order memristor has ...Considering the fact that memristors have the characteristics similar to biological synapses, a fractional-order multistable memristor is proposed in this paper. It is verified that the fractional-order memristor has multiple local active regions and multiple stable hysteresis loops, and the influence of fractional-order on its nonvolatility is also revealed. Then by considering the fractional-order memristor as an autapse of Hindmarsh–Rose(HR) neuron model, a fractional-order memristive neuron model is developed. The effects of the initial value, external excitation current, coupling strength and fractional-order on the firing behavior are discussed by time series, phase diagram, Lyapunov exponent and inter spike interval(ISI) bifurcation diagram. Three coexisting firing patterns, including irregular asymptotically periodic(A-periodic)bursting, A-periodic bursting and chaotic bursting, dependent on the memristor initial values, are observed. It is also revealed that the fractional-order can not only induce the transition of firing patterns, but also change the firing frequency of the neuron. Finally, a neuron circuit with variable fractional-order is designed to verify the numerical simulations.展开更多
A memristor-coupled heterogenous neural network consisting of two-dimensional(2D)FitzHugh–Nagumo(FHN)and Hindmarsh–Rose(HR)neurons with two time delays is established.Taking the time delays as the control parameters...A memristor-coupled heterogenous neural network consisting of two-dimensional(2D)FitzHugh–Nagumo(FHN)and Hindmarsh–Rose(HR)neurons with two time delays is established.Taking the time delays as the control parameters,the existence of Hopf bifurcation near the stable equilibrium point in four cases is derived theoretically,and the validity of the Hopf bifurcation condition is verified by numerical analysis.The results show that the two time delays can make the stable equilibrium point unstable,thus leading to periodic oscillations induced by Hopf bifurcation.Furthermore,the time delays in FHN and HR neurons have different effects on the firing activity of neural network.Complex firing patterns,such as quiescent state,chaotic spiking,and periodic spiking can be induced by the time delay in FHN neuron,while the neural network only exhibits quiescent state and periodic spiking with the change of the time delay in HR neuron.Especially,phase synchronization between the heterogeneous neurons is explored,and the results show that the time delay in HR neurons has a greater effect on blocking the synchronization than the time delay in FHN neuron.Finally,the theoretical analysis is verified by circuit simulations.展开更多
At present, many neuron models have been proposed, which can be divided into discrete neuron models and continuous neuron models. Discrete neuron models have the advantage of faster simulation speed and the ease of un...At present, many neuron models have been proposed, which can be divided into discrete neuron models and continuous neuron models. Discrete neuron models have the advantage of faster simulation speed and the ease of understanding complex dynamic phenomena. Due to the properties of memorability, nonvolatility, and local activity, locally active discrete memristors(LADMs) are also suitable for simulating synapses. In this paper, we use an LADM to mimic synapses and establish a Rulkov neural network model. It is found that the change of coupling strength and the initial state of the LADM leads to multiple firing patterns of the neural network. In addition, considering the influence of neural network parameters and the initial state of the LADM, numerical analysis methods such as phase diagram and timing diagram are used to study the phase synchronization. As the system parameters and the initial states of the LADM change, the LADM coupled Rulkov neural network exhibits synchronization transition and synchronization coexistence.展开更多
In order to understand the dominant factors of the physical properties of ice in ice thermodynamics and mechanics,in-situ observations of ice growth and decay processes were carried out.Two samplings were conducted in...In order to understand the dominant factors of the physical properties of ice in ice thermodynamics and mechanics,in-situ observations of ice growth and decay processes were carried out.Two samplings were conducted in the fast and steady ice growth stages.Ice pieces were used to observe ice crystals and gas bubbles in ice,and to measure the ice density.Vertical profiles of the type and size of ice crystals,shape and size of gas bubbles,and gas bubble content,as well as the ice density,were obtained.The results show that the upper layer of the ice pieces is granular ice and the lower layer is columnar ice;the average crystal size increases with the ice depth and remains steady in the fast and steady ice growth stages;the shape of gas bubbles in the upper layer of ice pieces is spherical with higher total content,and the shape in the middle and lower layers is cylinder with lower total content;the gas bubble size and content vary with the ice growth stage;and the ice density decreases with the increase of the gas bubble content.展开更多
In this paper,a fault tolerant control with the consideration of actuator fault for a networked control system (NCS) with packet loss is addressed.The NCS with data packet loss can be described as a switched system mo...In this paper,a fault tolerant control with the consideration of actuator fault for a networked control system (NCS) with packet loss is addressed.The NCS with data packet loss can be described as a switched system model.Packet loss dependent Lyapunov function is used and a fault tolerant controller is proposed respectively for arbitrary packet loss process and Markovian packet loss process.Considering a controlled plant with external energy-bounded disturbance,a robust H ∞ fault tolerant controller is designed for the NCS.These results are also expanded to the NCS with packet loss and networked-induced delay.Numerical examples are given to illustrate the effectiveness of the proposed design method.展开更多
The speciation and atomic structures of corrosion products in Ni-based alloys could provide basic information for understanding the Te corrosion mechanism.In this paper,two-dimensional synchrotron-radiation-induced gr...The speciation and atomic structures of corrosion products in Ni-based alloys could provide basic information for understanding the Te corrosion mechanism.In this paper,two-dimensional synchrotron-radiation-induced grazing incidence X-ray diffraction was used to characterize the corrosion products of a Ni–18%Cr binary alloy at temperatures from 600 to 1000℃.The results showed that a film of CrTe is preferentially formed when Te reacts with the Ni-based alloy at low temperatures(below 900℃),while CrTe and Ni3Te2 are formed at 900℃.Moreover,at a temperature of 1000℃,a solid solution is formed without any changes in the Ni–Cr substrate lattice parameters.Furthermore,X-ray absorption fine structure and wavelet transform analyses were used to investigate the atomic local structure of Te.The investigation indicated that Te atoms diffuse into the Ni–Cr substrate to form a substitutional Ni–Cr–Te solid solution at 1000℃.Notably,based on a discussion of the thermodynamics of the chemical reaction process,CrTe is considered to be the most stable and prevalent corrosion product due to its comparatively lower Gibbs free energy of formation.These results demonstrate that the Ni–18%Cr alloy is capable of resisting the diffusion of Te atoms.展开更多
In this study,pure Ni was demonstrated to protect the GH3535 alloy from Te vapor corrosion because of its strong absorption capacity.Severe Te corrosion of a single GH3535 alloy sample occurred in Te vapor at 700C,whi...In this study,pure Ni was demonstrated to protect the GH3535 alloy from Te vapor corrosion because of its strong absorption capacity.Severe Te corrosion of a single GH3535 alloy sample occurred in Te vapor at 700C,which manifested as complex surface corrosion products and deep intergranular cracks.However,when pure Ni and the GH3535 alloy were put together in the vessel,the GH3535 alloy was completely protected from Te corrosion at the expense of the pure Ni.Thermodynamic calculations proved that the preferential reaction between pure Ni and Te vapor reduced the activity of Te vapor considerably,preventing the corrosion of the GH3535 alloy.Our study reveals one potential approach for protecting the alloys used in molten-salt reactors from Te corrosion.展开更多
The embrittlement of nickel-based structural alloys by fission-produced tellurium(Te) is a major challenge for molten salt reactors(MSR). In this study, the effects of thermal exposure time on tellurium diffusion in a...The embrittlement of nickel-based structural alloys by fission-produced tellurium(Te) is a major challenge for molten salt reactors(MSR). In this study, the effects of thermal exposure time on tellurium diffusion in a candidate MSR structural alloy(Ni–16 Mo–7 Cr–4 Fe) and the consequent mechanical property degradation of the alloy were investigated through surrogate diffusion experiments at 700 °C. The results show that some tellurium reacted with the alloy to form tellurides on the surface,while some tellurium diffused into the alloy along grain boundaries. Ni_3Te_2 and CrTe were the most stable reaction products at the tested temperature, and the formation of CrTe on the surface induced the Cr depletion at grain boundaries of the alloy. The diffusion depth of Te increased gradually with thermal exposure time, and thediffusion rate kept stable within the test duration of up to3000 h. The Te diffusion in the alloy caused the embrittlement of grain boundaries, inducing crack formation and strength degradation in tensile test at room temperature.展开更多
BACKGROUND Schizophrenia(SCZ)is a complex disease which can be affected by both genetic and environmental factors.Prenatal famine exposure may cause changes in DNA methylation levels of genes.Meanwhile,maternal nutrit...BACKGROUND Schizophrenia(SCZ)is a complex disease which can be affected by both genetic and environmental factors.Prenatal famine exposure may cause changes in DNA methylation levels of genes.Meanwhile,maternal nutrition during pregnancy is a pivotal environmental factor in the development of SCZ.DNA methylation may be an intermediate factor mediating exposure to famine during pregnancy and SCZ,and DNA methylation quantitative trait loci might serve as a promising tool for linking SCZ and prenatal famine.AIM To analyze the association between prenatal famine exposure and SCZ risk in Northeast Han Chinese through analysis of DNA methylation related loci.METHODS A total of 954 Han Chinese from Northeast China were recruited,including 443 patients with SCZ and 511 healthy controls.The participants were further divided into famine(born in 1960-1962)and non-famine(born in 1963-1965)groups to investigate the effect of prenatal famine exposure.Four single-nucleotide polymorphisms(SNPs)selected according to the relevant literature were genotyped,namely,rs11917047 in PTPRG,rs2239681 in IGF2,rs3842756 in INSIGF,and rs61955196 in ABCB9.DNA were extracted from peripheral blood samples,and the genotypes of these SNP loci were detected using the improved Multiple Ligase Detection Reaction multiple SNP typing technique.The associations of the DNA methylation related SNPs with SCZ risk and prenatal famine,and their interactions were analyzed using logistic regression analysis and generalized multifactor dimensionality reduction(GMDR)software.RESULTS Based on the sequencing data,genotype distributions and allele frequencies of the four selected SNPs were determined.All genotype frequencies of the four SNPs in the healthy control group were tested for deviation from Hardy-Weinberg equilibrium(P>0.05).Logistic regression analysis showed that rs61955196 was significantly associated with SCZ risk in the log-additive model[odds ratio(OR):1.22;95%confidence interval(CI):1.01-1.48;P=0.040].We also found that the rs61955196 allele was related with an enhanced risk of SCZ(G>C,OR:1.22;95%CI:1.01-1.47;P=0.042).However,no associations were observed between rs11917047,rs2239681,or rs3842756 and SCZ risk.Under the optimal genetic model,no significant association of famine with the four SNPs was seen.Though the gene–gene interactions between rs2239681 and rs61955196 were found in GMDR analysis,none of the gene-gene interactions and gene-famine interactions were associated with the risk of SCZ.CONCLUSION Our study suggested that rs61955196 in ABCB9 is associated with SCZ susceptibility in Northeast Han Chinese,providing insight into genetic effects on SCZ.展开更多
Objective:Magnetic resonance imaging(MRI)studies have demonstrated anatomical and functional alterations of brain regions in patients with migraine,and the efficacy of acupuncture for migraine could regulate these abn...Objective:Magnetic resonance imaging(MRI)studies have demonstrated anatomical and functional alterations of brain regions in patients with migraine,and the efficacy of acupuncture for migraine could regulate these abnormal alterations.However,its pathogenesis remains ambiguous,and inconsistent results have been reported.The purpose of this study was to explore abnormal structural and functional alterations in patients with migraine using voxel-based morphometry(VBM)analysis and a seed-based functional connectivity(FC)approach and to provide a basis for future research.Methods:The study recruited 34 patients with migraine and 38 healthy controls who underwent structural and resting-state functional magnetic resonance imaging(fMRI).VBM was evaluated across the whole brain,and group differences in the gray matter(GM)were compared.The significantly altered GM volumes considered as the seeding area were further calculated for the FC of the whole brain.The correlation between structural or functional changes of the brain and clinical features was also evaluated.Results:Patients with migraine manifested higher GM volumes in the left occipital lobe than healthy controls.Seed-based analyses demonstrated reduced FC between the left occipital lobe and right inferior frontal gyrus,extending to the anterior cingulate cortex(ACC)and right insula.Decreased FC in the left ACC was positively correlated with visual analog scale(VAS)and self-rating anxiety scale(SAS).展开更多
基金This work was supported by the Guangdong Basic and Applied Basic Research Fund,No.2022A1515111193the Guangzhou Science and technology plan project,No.2023A04J0581.
文摘BACKGROUND Solitary rectal ulcer syndrome(SRUS)is a rare rectal disease with unknown etiology.Data on the genetic background in SRUS is lacking.CASE SUMMARY Here,we report the first case of SRUS in a mother-son relationship.Gene sequencing was conducted on the whole family,which revealed an inherited CHEK2 p.H371Y mutation.The experiment preliminarily revealed that the CHEK2 mutation did not affect the expression of CHEK2 protein,but affected the function of CHEK2,resulting in the expression level changes of downstream genes such as CDC25A.CONCLUSION SRUS is a genetic susceptibility disease where CHEK2 p.H371Y mutation may play a crucial role in the development and prognosis of SRUS.
基金supported by the National key research and development program of China(Nos.2016YFB0700401 and 2016YFB0700404)Natural Science Foundation of Shanghai(Nos.19ZR1468200 and 18ZR1448000)+2 种基金National Natural Science Foundation of China(Nos.51671154,51601213 and 51671122)Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA02004210)Youth Innovation Promotion Association,Chinese Academy of Science(No.2019264)
文摘From a safety point of view, it is important to study the damages and reliability of molten salt reactor structural alloy materials, which are subjected to extreme environments due to neutron irradiation, molten salt corrosion, fission product attacks, thermal stress, and even combinations of these. In the past few years, synchrotron radiation-based materials characterization techniques have proven to be effective in revealing the microstructural evolution and failure mechanisms of the alloys under surrogating operation conditions. Here, we review the recent progress in the investigations of molten salt corrosion,tellurium(Te) corrosion, and alloy design. The valence states and distribution of chromium(Cr) atoms, and the diffusion and local atomic structure of Te atoms near the surface of corroded alloys have been investigated using synchrotron radiation techniques, which considerably deepen the understandings on the molten salt and Te corrosion behaviors. Furthermore, the structure and size distribution of the second phases in the alloys have been obtained, which are helpful for the future development of new alloy materials.
基金supported by the project of the China Geological Survey(DD20190167)the National Key Research and Development Program of China(2018YFC0604101,2018YFC0604106)+1 种基金the Special Funds for Basic Scientific Research of the Institute of mineral resources,Chinese Academy of Geological Sciences(kk2017)the National Natural Science Foundation of China(42002103,41902097).
文摘Many large and super-large copper deposits have been discovered and explored in the Tibet Plateau,which makes it the most important copper resource reserve and development base in China.Based on the work of the research team,the paper summarizes the geological characteristics of the main copper deposits in Tibet and puts forward a further prospecting direction.A series of large accumulated metal deposits or ore districts from subduction of Tethys oceanic crust to India-Asia collisionhave been discovered,such as Duolong Cu(Au)ore district and Jiama copper polymetallic deposit.The ore deposits in the Duolong ore district are located in the lowstand domain,the top of lowstand domain,and the highstand domain of the same magmatic-hydrothermal metallogenic system,and their relative positions are the indicators for related deposits in the Bangong Co-Nujiang metallogenic belt.The polycentric metallogenic model of the Jiama copper polymetallic deposit is an important inspiration for the exploration of the porphyry mineralization related to collision orogeny.Further mineral exploration in the Tibet Plateau should be focused on the continental volcanic rocks related to porphyry-epithermal deposits,orogenic gold deposits,hydrothermal Pb-Zn deposits related to nappe structures,skarn Cu(Au)and polymetallic deposits,and the Miocene W-Sn polymetallic deposits.
基金supported by the National Natural Science Foundation of China (Nos. 11975021,12175321,11675275,U1832204,and U1932101)National Key Research and Development Program of China (Nos. 2020YFA0406300 and 2020YFA0406400)+6 种基金Guangdong Basic and Applied Basic Research Foundation (No.2021A1515012039)State Key Laboratory of Nuclear Physics and Technology,Peking University (Nos. NPT2020KFY04 and NPT2020KFY05)Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA10010900)Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility ProgramFundamental Research Funds for the Central UniversitiesSun Yat-sen University,National College Students Science and Technology Innovation ProjectUndergraduate Base Scientific Research Project of Sun Yat-sen University
文摘Detector and event visualization are essential parts of the software used in high-energy physics(HEP)experiments.Modern visualization techniques and multimedia production platforms such as Unity provide impressive display effects and professional extensions for visualization in HEP experiments.In this study,a method for automatic detector description transformation is presented,which can convert the complicated HEP detector geometry from GDML in offline software to 3D modeling in Unity.The method was successfully applied in the BESIII experiment and can be further developed into applications such as event displays,data monitoring,or virtual reality.It has great potential in detector design,offline software development,physics analysis,and outreach for next-generation HEP experiments as well as applications in nuclear techniques for the industry.
基金financially supported by the National Natural Science Foundation of China(No.51974351No.51704322+1 种基金Major Program,No.51991361)the National Science and Technology Major Project of China(No.2016ZX05040-005)。
文摘Regulating rheological properties of water-based drilling fluids has always been a hot topic.This paper proposed a new method for regulating rheological properties of water-based drilling fluids by ultrasonic field.The experimental results showed that the ultrasound increased the viscosity and yield point of bentonite suspension by reducing the particle size of clay,destroying the network structure between clay particles,increasing the mud yield and the cation exchange capacity of bentonite,and promoting the hydration dispersion of bentonite.The change of rheological property showed a memory effect at room temperature and high temperature.Besides,the ultrasonic energy affected the network structure between clays and polymer chains,thus regulating the rheological properties of the bentonite-polymer system.For two types of drilling fluids investigated,the rheology of the poly-sulfonate drilling fluid was regulated by damaging the grid structure between additives and clays by low-power ultrasound and reducing the clay particle size by high-power ultrasound,while the rheology of the deep-water drilling fluid was mainly regulated by disentangling the spatial grid structure between additives.Additionally,ultrasound showed no effect on the lubricity,inhibition and stability of drilling fluids,which proved the feasibility of ultrasound to regulate rheological properties of water-based drilling fluids.
基金financially supported by the National Natural Science Foundation of China(Nos.U2032205,51971238,and 52005492)the Shanghai Outstanding Academic Leaders Plan(21XD1404300)+2 种基金the Natural Science Foundation of Shanghai(Nos.18ZR1448000,19ZR 1468200,20ZR1468600,and 21XD1404300)the Shanghai Sailing Program(Grant No.19YF1458300)the Youth Innovation Promotion Association,Chinese Academy of Science(No.2019264).
文摘An explosion-welded technology was induced to manufacture the GH3535/316H bimetallic plates to provide a more cost-effective structural material for ultrahigh temperature,molten salt thermal storage systems.The microstructure of the bonding interfaces were extensively investigated by scanning electron microscopy,energy dispersive spectrometry,and an electron probe microanalyzer.The bonding interface possessed a periodic,wavy morphology and was adorned by peninsula-or island-like transition zones.At higher magnification,a matrix recrystallization region,fine grain region,columnar grain region,equiaxed grain region,and shrinkage porosity were observed in the transition zones and surrounding area.Electron backscattered diffraction demonstrated that the strain in the recrystallization region of the GH3535 matrix and transition zone was less than the substrate.Strain concentration occurred at the interface and the solidification defects in the transition zone.The dislocation substructure in 316H near the interface was characterized by electron channeling contrast imaging.A dislocation network was formed in the grains of 316H.The microhardness decreased as the distance from the welding interface increased and the lowest hardness was inside the transition zone.
基金Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences(No.2019-I2M-5-023)Hainan Provincial Science and Technology Major Project(No.ZDKJ201804)+2 种基金National Natural Science Foundation of China(No.81871611)National Natural Science Foundation of China(No.81760352)Project of Hainan Provincial Department of Education(No.Hnjg2019ZD-16)
文摘1.Introduction Sudden cardiac death(SCD)refers to sudden death due to a variety of cardiac causes.It is manifested as a sudden loss of consciousness,cardiac arrest,and respiratory arrest and generally shows early symptoms that are atypical and not easily detected[1].According to a recent study,nearly 544000 patients suffer from SCD every year in China[2].
基金Project supported by the National Key Research and Development Program of China (Grant No.2018AAA0103300)the National Natural Science Foundation of China (Grant Nos.62171401 and 62071411)。
文摘Considering the fact that memristors have the characteristics similar to biological synapses, a fractional-order multistable memristor is proposed in this paper. It is verified that the fractional-order memristor has multiple local active regions and multiple stable hysteresis loops, and the influence of fractional-order on its nonvolatility is also revealed. Then by considering the fractional-order memristor as an autapse of Hindmarsh–Rose(HR) neuron model, a fractional-order memristive neuron model is developed. The effects of the initial value, external excitation current, coupling strength and fractional-order on the firing behavior are discussed by time series, phase diagram, Lyapunov exponent and inter spike interval(ISI) bifurcation diagram. Three coexisting firing patterns, including irregular asymptotically periodic(A-periodic)bursting, A-periodic bursting and chaotic bursting, dependent on the memristor initial values, are observed. It is also revealed that the fractional-order can not only induce the transition of firing patterns, but also change the firing frequency of the neuron. Finally, a neuron circuit with variable fractional-order is designed to verify the numerical simulations.
基金the National Natural Science Foundations of China(Grant Nos.62171401 and 62071411).
文摘A memristor-coupled heterogenous neural network consisting of two-dimensional(2D)FitzHugh–Nagumo(FHN)and Hindmarsh–Rose(HR)neurons with two time delays is established.Taking the time delays as the control parameters,the existence of Hopf bifurcation near the stable equilibrium point in four cases is derived theoretically,and the validity of the Hopf bifurcation condition is verified by numerical analysis.The results show that the two time delays can make the stable equilibrium point unstable,thus leading to periodic oscillations induced by Hopf bifurcation.Furthermore,the time delays in FHN and HR neurons have different effects on the firing activity of neural network.Complex firing patterns,such as quiescent state,chaotic spiking,and periodic spiking can be induced by the time delay in FHN neuron,while the neural network only exhibits quiescent state and periodic spiking with the change of the time delay in HR neuron.Especially,phase synchronization between the heterogeneous neurons is explored,and the results show that the time delay in HR neurons has a greater effect on blocking the synchronization than the time delay in FHN neuron.Finally,the theoretical analysis is verified by circuit simulations.
基金the Natural Science Foundation of Hunan Province, China (Grant Nos. 2022JJ30572, 2022JJ30160, and 2021JJ30671)the National Natural Science Foundations of China (Grant No. 62171401)the Key Project of Science and Technology of Shunde District (Grant No. 2130218002544)。
文摘At present, many neuron models have been proposed, which can be divided into discrete neuron models and continuous neuron models. Discrete neuron models have the advantage of faster simulation speed and the ease of understanding complex dynamic phenomena. Due to the properties of memorability, nonvolatility, and local activity, locally active discrete memristors(LADMs) are also suitable for simulating synapses. In this paper, we use an LADM to mimic synapses and establish a Rulkov neural network model. It is found that the change of coupling strength and the initial state of the LADM leads to multiple firing patterns of the neural network. In addition, considering the influence of neural network parameters and the initial state of the LADM, numerical analysis methods such as phase diagram and timing diagram are used to study the phase synchronization. As the system parameters and the initial states of the LADM change, the LADM coupled Rulkov neural network exhibits synchronization transition and synchronization coexistence.
基金supported by the National Natural Science Foundation of China (Grant No.50879008)the Open Fund of State Key Laboratory of Frozen Soil Engineering (Grant No. SKLFSE200904)+1 种基金the Vilho,Yrj and Kalle Visl Fund of the Finnish Academy of Sciences and Lettersthe Norwegian Research Council Project AMORA (Grant No.193592/S30)
文摘In order to understand the dominant factors of the physical properties of ice in ice thermodynamics and mechanics,in-situ observations of ice growth and decay processes were carried out.Two samplings were conducted in the fast and steady ice growth stages.Ice pieces were used to observe ice crystals and gas bubbles in ice,and to measure the ice density.Vertical profiles of the type and size of ice crystals,shape and size of gas bubbles,and gas bubble content,as well as the ice density,were obtained.The results show that the upper layer of the ice pieces is granular ice and the lower layer is columnar ice;the average crystal size increases with the ice depth and remains steady in the fast and steady ice growth stages;the shape of gas bubbles in the upper layer of ice pieces is spherical with higher total content,and the shape in the middle and lower layers is cylinder with lower total content;the gas bubble size and content vary with the ice growth stage;and the ice density decreases with the increase of the gas bubble content.
基金supported by National Natural Science Foundation of China (No. 60874052)
文摘In this paper,a fault tolerant control with the consideration of actuator fault for a networked control system (NCS) with packet loss is addressed.The NCS with data packet loss can be described as a switched system model.Packet loss dependent Lyapunov function is used and a fault tolerant controller is proposed respectively for arbitrary packet loss process and Markovian packet loss process.Considering a controlled plant with external energy-bounded disturbance,a robust H ∞ fault tolerant controller is designed for the NCS.These results are also expanded to the NCS with packet loss and networked-induced delay.Numerical examples are given to illustrate the effectiveness of the proposed design method.
基金supported by the National Key Research and Development Program of China(No.2016YFB0700404)National Natural Science Foundation of China(No.U1732267)+2 种基金National Natural Science Foundation of China(Nos.51671122 and 51671154)Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA02004210)Talent Development Fund of Shanghai(No.201650)
文摘The speciation and atomic structures of corrosion products in Ni-based alloys could provide basic information for understanding the Te corrosion mechanism.In this paper,two-dimensional synchrotron-radiation-induced grazing incidence X-ray diffraction was used to characterize the corrosion products of a Ni–18%Cr binary alloy at temperatures from 600 to 1000℃.The results showed that a film of CrTe is preferentially formed when Te reacts with the Ni-based alloy at low temperatures(below 900℃),while CrTe and Ni3Te2 are formed at 900℃.Moreover,at a temperature of 1000℃,a solid solution is formed without any changes in the Ni–Cr substrate lattice parameters.Furthermore,X-ray absorption fine structure and wavelet transform analyses were used to investigate the atomic local structure of Te.The investigation indicated that Te atoms diffuse into the Ni–Cr substrate to form a substitutional Ni–Cr–Te solid solution at 1000℃.Notably,based on a discussion of the thermodynamics of the chemical reaction process,CrTe is considered to be the most stable and prevalent corrosion product due to its comparatively lower Gibbs free energy of formation.These results demonstrate that the Ni–18%Cr alloy is capable of resisting the diffusion of Te atoms.
基金the National Natural Science Foundation of China(Nos.U2032205,52171023,51971238,and 52005492)Natural Science Foundation of Shanghai(Nos.20ZR1468600 and 19ZR1468200)+1 种基金Shanghai Sailing Program(No.19YF1458300)the Youth Innovation Promotion Association,Chinese Academy of Science(No.2019264)。
文摘In this study,pure Ni was demonstrated to protect the GH3535 alloy from Te vapor corrosion because of its strong absorption capacity.Severe Te corrosion of a single GH3535 alloy sample occurred in Te vapor at 700C,which manifested as complex surface corrosion products and deep intergranular cracks.However,when pure Ni and the GH3535 alloy were put together in the vessel,the GH3535 alloy was completely protected from Te corrosion at the expense of the pure Ni.Thermodynamic calculations proved that the preferential reaction between pure Ni and Te vapor reduced the activity of Te vapor considerably,preventing the corrosion of the GH3535 alloy.Our study reveals one potential approach for protecting the alloys used in molten-salt reactors from Te corrosion.
基金supported by the National key research and development program of China(No.2016YFB0700404)the National Natural Science Foundation of China(Nos.51371188,51671122,51671154,51601213,51501216)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA02004210)the Shanghai Sailing Program(No.16YF1414300)the Talent development fund of Shanghai(No.201650)
文摘The embrittlement of nickel-based structural alloys by fission-produced tellurium(Te) is a major challenge for molten salt reactors(MSR). In this study, the effects of thermal exposure time on tellurium diffusion in a candidate MSR structural alloy(Ni–16 Mo–7 Cr–4 Fe) and the consequent mechanical property degradation of the alloy were investigated through surrogate diffusion experiments at 700 °C. The results show that some tellurium reacted with the alloy to form tellurides on the surface,while some tellurium diffused into the alloy along grain boundaries. Ni_3Te_2 and CrTe were the most stable reaction products at the tested temperature, and the formation of CrTe on the surface induced the Cr depletion at grain boundaries of the alloy. The diffusion depth of Te increased gradually with thermal exposure time, and thediffusion rate kept stable within the test duration of up to3000 h. The Te diffusion in the alloy caused the embrittlement of grain boundaries, inducing crack formation and strength degradation in tensile test at room temperature.
基金National Natural Science Foundation of China,No.81673253Jilin Provincial Ministry of Education S&T Project,No.JJKH20190091KJ。
文摘BACKGROUND Schizophrenia(SCZ)is a complex disease which can be affected by both genetic and environmental factors.Prenatal famine exposure may cause changes in DNA methylation levels of genes.Meanwhile,maternal nutrition during pregnancy is a pivotal environmental factor in the development of SCZ.DNA methylation may be an intermediate factor mediating exposure to famine during pregnancy and SCZ,and DNA methylation quantitative trait loci might serve as a promising tool for linking SCZ and prenatal famine.AIM To analyze the association between prenatal famine exposure and SCZ risk in Northeast Han Chinese through analysis of DNA methylation related loci.METHODS A total of 954 Han Chinese from Northeast China were recruited,including 443 patients with SCZ and 511 healthy controls.The participants were further divided into famine(born in 1960-1962)and non-famine(born in 1963-1965)groups to investigate the effect of prenatal famine exposure.Four single-nucleotide polymorphisms(SNPs)selected according to the relevant literature were genotyped,namely,rs11917047 in PTPRG,rs2239681 in IGF2,rs3842756 in INSIGF,and rs61955196 in ABCB9.DNA were extracted from peripheral blood samples,and the genotypes of these SNP loci were detected using the improved Multiple Ligase Detection Reaction multiple SNP typing technique.The associations of the DNA methylation related SNPs with SCZ risk and prenatal famine,and their interactions were analyzed using logistic regression analysis and generalized multifactor dimensionality reduction(GMDR)software.RESULTS Based on the sequencing data,genotype distributions and allele frequencies of the four selected SNPs were determined.All genotype frequencies of the four SNPs in the healthy control group were tested for deviation from Hardy-Weinberg equilibrium(P>0.05).Logistic regression analysis showed that rs61955196 was significantly associated with SCZ risk in the log-additive model[odds ratio(OR):1.22;95%confidence interval(CI):1.01-1.48;P=0.040].We also found that the rs61955196 allele was related with an enhanced risk of SCZ(G>C,OR:1.22;95%CI:1.01-1.47;P=0.042).However,no associations were observed between rs11917047,rs2239681,or rs3842756 and SCZ risk.Under the optimal genetic model,no significant association of famine with the four SNPs was seen.Though the gene–gene interactions between rs2239681 and rs61955196 were found in GMDR analysis,none of the gene-gene interactions and gene-famine interactions were associated with the risk of SCZ.CONCLUSION Our study suggested that rs61955196 in ABCB9 is associated with SCZ susceptibility in Northeast Han Chinese,providing insight into genetic effects on SCZ.
基金Supported by National Natural Science Foundation of China Youth Fund:82004197Department of Science and Technology,National Administration of Traditional Chinese Medicine:GZY-KJS-2022-029The fifth batch of national research and training programs for clinical talents of traditional Chinese medicine,Project for new teachers of Beijing University of Chinese Medicine:2020-JYB-XJSJJ-045。
文摘Objective:Magnetic resonance imaging(MRI)studies have demonstrated anatomical and functional alterations of brain regions in patients with migraine,and the efficacy of acupuncture for migraine could regulate these abnormal alterations.However,its pathogenesis remains ambiguous,and inconsistent results have been reported.The purpose of this study was to explore abnormal structural and functional alterations in patients with migraine using voxel-based morphometry(VBM)analysis and a seed-based functional connectivity(FC)approach and to provide a basis for future research.Methods:The study recruited 34 patients with migraine and 38 healthy controls who underwent structural and resting-state functional magnetic resonance imaging(fMRI).VBM was evaluated across the whole brain,and group differences in the gray matter(GM)were compared.The significantly altered GM volumes considered as the seeding area were further calculated for the FC of the whole brain.The correlation between structural or functional changes of the brain and clinical features was also evaluated.Results:Patients with migraine manifested higher GM volumes in the left occipital lobe than healthy controls.Seed-based analyses demonstrated reduced FC between the left occipital lobe and right inferior frontal gyrus,extending to the anterior cingulate cortex(ACC)and right insula.Decreased FC in the left ACC was positively correlated with visual analog scale(VAS)and self-rating anxiety scale(SAS).
